MacBook Pro - Extending battery time?

I am about to go on a 10 hour flight. I have a macbook pro, about a year old. The battery life sucks...I get maybe 2 hours out of the battery at best. I have a spare battery as well. It also only gets about 2 hours. But I'd love to be able to work on a project for most of the flight. All I would need open is Photoshop to work on my project.

Can anyone suggest anything to extend the battery time? (short of asking someone in a better class of service on the plane if I can recharge the battery with their outlet ;-)

Set the screen brightness all the way down until you are comfortable reading. Turn off bluetooth, and wireless networking. Turn off the light underneath the keyboard. And only use the applications you are actually going to use and shut down everything else. Remove any CD or DVD you might have in the machine, to prevent it to spin up.